<HTML><HEAD><TITLE>round(+Number, -Result)</TITLE>
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<H1>round(+Number, -Result)</H1>
Rounds Number to the nearest integral value of the same type
<DL>
<DT><EM>Number</EM></DT>
<DD>A number.
</DD>
<DT><EM>Result</EM></DT>
<DD>A variable or number.
</DD>
</DL>
<H2>Description</H2>
   This predicate is used by the ECLiPSe compiler to expand evaluable
   arithmetic expressions.  So the call to round(Number, Result) is
   equivalent to
<PRE>
    Result is round(Number)
</PRE>
    which should be preferred for portability.
<P>
   This operation works on all numeric types. The result value is the
   integral value that is closest to Number (rounding to nearest). If
   Number is exactly in the middle between two integers, the result
   is the even one.
<P>
   The result type is the same as the argument type.  To convert the
   type to integer, use integer/2.
<P>
   In coroutining mode, if Number is uninstantiated, the call to round/2
   is delayed until this variable is instantiated.

<P>

<H3>Modes and Determinism</H3><UL>
<LI>round(+, -) is det
</UL>
<H3>Exceptions</H3>
<DL>
<DT><EM>(4) instantiation fault </EM>
<DD>Number is not instantiated (non-coroutining mode only).
<DT><EM>(24) number expected </EM>
<DD>Number is not of a numeric type.
</DL>
<H2>Examples</H2>
<PRE>
Success:
      round(1.49, 1.0).
      round(1.5, 2.0).          (odd integer part)
      round(2.5, 2.0).
      round(2.51, 3.0).         (even integer part)
      round(3.5, 4.0).
      round(-6.4, Result).      (gives Result = -6.0)
      round(3, 3).
Fail:
      round(1, 0.0).
      round(0.5, 0).
      round(1, r).
Error:
      round(A, 6.0).                   (Error 4).
      round(4 + 2.3, 6.0).             (Error 24).



</PRE>
<H2>See Also</H2>
<A HREF="../../kernel/arithmetic/is-2.html">is / 2</A>, <A HREF="../../kernel/arithmetic/floor-2.html">floor / 2</A>, <A HREF="../../kernel/arithmetic/ceiling-2.html">ceiling / 2</A>, <A HREF="../../kernel/arithmetic/truncate-2.html">truncate / 2</A>, <A HREF="../../kernel/arithmetic/integer-2.html">integer / 2</A>
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